Limit switch operating mechanism



March 30, 1954 R. B. IMMEL ETAL LIMIT SWITCH OPERATING MECHANISM 2 Sheets-Sheet 1 Filed July 28, 1951 INVENTORS Ralph BzlmrneLLowrence Pierce 0ng StonleyKmonk,Jr. FAA/f ATTORNEY March 30, 1954 R. B. IMMEL ETAL LIMIT SWITCH OPERATING MECHANISM 2 Sheets-Sheet 2 Filed July 28, 1 951 INVENTORS Ralph B.Immel,Luwrence Pierce ord Stanley Kmonk,Jr. M5

WITNESSES: 1%7 /%%7. 7

ATTORNEY Patented Mar. 30, 1954 gen ra UNITED STATES A'E'ENT OFFICE LIMIT SWITCH OPERATING MECHANISM Ralph E. Immel and Lawrence Pierce, Williams- ..ville, N. Y., and Stanley Kmonk, Jr., Wilmerding, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 28, 1951, Serial No. 239,142

13 Claims. 1

Our invention relates to switches and, more particularly, to switch operating mechanisms, as applied to limit switches and other applications.

Limit switch operating mechanisms are well known in the prior art, but since limit switch service, particularly for some applications, requires many operations per minute over long periods of time, the useful life in terms of number of operations is rather limited for most prior art devices. Further, most prior art limit switch operating mechanisms are clumsy, bulky, and expensive, and very often the mechanisms do not take advantage of existing switches that may be operated by the operating mechanisms.

One broad object of our invention is the provision of a simple, low cost, and reliable operating mechanism for a well known plunger operated snap switch.

A more specific object of our invention is the provision of an operating mechanism for translating the rotary motion of a lever actuated by some machine, as a planer platen, into linear motion perpendicular to the plane of the rotary motion.

A specific object of our invention is the provision of applying linear motion to one end of a spring fixed in position at the other end along the axis of a spring to thus flex the spring to produce a movement of the mid-portion of the spring perpendicular to the spring axis. l A further object of our invention is the provision in the mechanical structure of a limit switch or similar device, an elongated slightly bowed leaf spring mounted on a base so that the ends may be moved toward and away from each other to thus produce a highly amplified mechanical movement near the middle of the spring at substantially right angles to the direction of relative movement of the ends of the spring.

The objects stated are merel illustrative of other objects of our invention that will become more apparent from a study of the following specification and the accompanying drawings, in which:

Figure l is a vertical section through the housing showing a side view of an embodiment of our invention;

Fig. 2 is a view along line II-II showing a rear view of our invention;

Fig. 3 is an exploded view of the limit switch operating mechanism;

Fig. 4 is a vertical sectional view through the hgusing showing a side view of a modification of our invention, with the parts in a non-operated position;

Fig. 5 is a vertical sectional view through the housing showing the parts, of the showing in Fig. 4, in an activated position;

Fig. 6 is a vertical sectional view on line VL-VI of Fig. 4; and

Fig. 7 is a vertical sectional view through the housing showing a side view of a further modification of our invention.

From the showing in Fig. 1, it will be apparent that the base i consists of the front or cover portion 2 and the rear portion 3. The rear portion houses the switch s and may be designated the switch casing. This switch 4 is of a well-known plunger actuated type with the plunger 5 projecting from the switch casing and the switch operating with a snap action upon an axial movement of the plunger 5 through a given distance. The switch 4 is rigidly mounted on the cover 2 by means of the bolts 6 and l threaded into the cover 2. Suitable sleeves 8 and 9 of selected length surround the bolts 5 and '5, respectively, and thus provide for the proper spacing of the switch 4 from the switch operating mechanism. The sleeves 8 and 9 may also be hollow studs cast integral with the cover 2.

The operating mechanism consists of a bearing sleeve It rigidl fixed into the cover 2. This sleeve IE has the shoulder and right end fitting into the cover 2 and the left end projecting into the case i to form, on its outer surface, a bearing for the clevis [2. The inside of the sleeve forms a snug bearing for the shaft It.

In assembled relation, the shaft 23 projects beyond the front of the cover to receive the actuating lever M. This lever M is rigidly secured to the shaft It by the set screw it. The lever it carries the roller it which roller is in use disposed to be actuated by some dog on a machine, as for instance a dog mounted on a planer platen.

The clevis l2 has the bearing opening :1 and the opening 18. The opening I? provides a snug but free bearing for the clevis I2 whereas the opening l8 receives the sleeve 8 and is suificiently large, as will be clear from Fig. 2, to allow for a selected angular motion of the clevis 2.

The clevis l2 has the sleeves l9 and 26 mounted between the facing ends of the clevis. The sleeves l9 and 20 are held in place by the rivets 2| and 22, respectively.

In assembled relation the spring 23 is disposed over the left end of sleeve lil Within the clevis with the end 24 behind the sleeve l 9 and the end 25 in front of the sleeve I9.

The sleeve 29 is provided with the groove 26 for receiving the upper knife-edged arcuate end of the spring 21. The cover 2 is provided with the grooved stud 28 for receiving the lower knifeedged arcuate end of the spring 21. The cover 2 also has the projection 29 to prevent the spring 21 from being bowed out toward the front. In use the spring is under stress so that it will always be bowed out toward the left, as seen in Fig. l, to be just touching the plunger when the plunger 5 has not been actuated toward the left.

The left end of shaft l3 carries the actuator 30. This actuator is rigidly fixed to shaft 13 and thus imparts the same angular movement to the finger 3| on the actuator 30 that is imparted to the actuator by the lever I4 as it is operated.

In operation, if the actuating dog motion is from right to left in Fig. 2, then the finger 3| moves counterclockwise against the spring arm 25. Since the spring is chosen rather stifi and is under stress, the other spring arm 24 actuates the clevis i2 counterclockwise about the bearing sleeve it until the sleeve 8 engages the top of the opening it. Further, counterclockwise motion of the clevis I2 is thus arrested, but counterclockwise motion that did take place was sufiicient to bow the spring 21 sufficiently to operate the switch 4.

The sleeve e does not, however, arrest the counterclockwise motion of lever 14 because the finger 3| merely moves the spring end 25 counterclockwise whereas the spring end 25 does not follow.

In practice, the actuating dog usually moves over and beyond the roller to the left and on the return stroke actuates the lever I4 clockwise moving over and beyond the roller to the right.

Upon a release of the lever M from a counterclockwise motion, the spring 2'! and the spring 23 restore the parts to the position shown in Fig. 2, and upon movement of lever 14 in a clockwise direction, the clevis I2 is not moved at all because spring end 24 only moves clockwise, whereas the spring end 25 remains in the position shown.

In the modification, the base 4| consists of the front or covering 42 and the switch housing 43 for the plunger actuated switch 44 having the operating plunger 45. The switch 44 is held to the cover 42 by the bolts 46 and 4?, with the parts being so selected that the plunger is in proper spaced relation to the plunger actuating spring 61.

The operating mechanism includes the bearing sleeve '50 rigidly fixed in the cover 42. The bearing sleeve 56 receives the shaft 53 to which the crank-arm 54 is rigidly secured. The crank-arm 54 carries the roller 56 for coaction with a suitable dog on a machine with which our apparatus is associated.

The inner end of the shaft 53 carries the eccentric disc or cam 51 rigidly secured to the shaft. This cam 51 fits snugly but rotatably into the upper end of the slide actuating link 58. The lower end of the link 58 is provided with a bearing opening for receiving the stud 59 rigidly mounted on the slide 60.

The Slide 60 is disposed for rectilinear vertical motion in suitable guides in the cover 42. The upper end of the slide 60 is provided with a rearwardly projecting lug 6i forming an upper end bearing for the spring Bl. The cover 42 is provided with a bearing notch for receiving the lower end of the spring 61. The rear face of the slide 6! is provided with the button 66 for providing the spring 61 with a bowed deflection. The spring 6'! is disposed in its end bearings in a slightly stressed position 'so that it does not fall out and will always be in position to be bowed out 4 toward the left, as shown in Fig. 5, when the slide Si is moved vertically downward.

In operation, when the dog on the machine actuates the roller 56 and thus the arm 54 in a rotary motion, the eccentric cam 57 moves the link 58 downwardly and thus forces the slide 6| down. This operation bows the spring 67 in the direction shown in Fig. 5 and the switch actuating plunger 45 is thus depressed and the switch 44 is operated.

In Fig. 7, we show certain parts of our invention reduced to their simplest structures.

The reference characters H, '12, I3, l4, 15, TB, and I1 designate the elements that correspond to elements 4!, 42, 43, 44, 45, 46 and 41 of Figs. 4 and 5.

The spring 91 is disposed in a bowed condition between the notch in the cover 12 and a similar notch in the spring deflecting plunger 9|. The stud 95 prevents the spring 91 from taking a bowed position such that depression of the plunger s; would cause the spring 91 to bow outwardly to the right.

The showing in Fig. 7 is extremely simple and cheap and provides for the actuation of a second plunger longitudinally of its axis by an operation of a first plunger, having its axis disposed at right angles to the second plunger, longitudinally of its axis.

While we have shown and described but one embodiment of our invention, it will be apparent to those skilled in the art that modifications may be made all within the spirit of our invention. We, therefore, do not wish to be limited to the details of the showing made but only by the scope of the claims hereto appended.

We claim as our invention:

1. In a switch actuating mechanism for a plunger actuated switch, in combination, a base, a straight fiat spring, a bearing member mounted on said base designed to receive one end of the fiat spring, a rotary element mounted for limited rotary motion on said base, a second bearing member, said second bearing member being mounted on the rotary element a short distance from the axis of rotation of the rotary element and being designed to receive the other end of the flat spring, said bearing members, when the rotary element has not been rotated through its limited angular rotation, being so disposed with reference to each other that the spring is slightly bowed and is contiguous to the switch plunger, and means for rotating the rotary element in a direction to decrease the distance between the bearing members to thus bow the spring still more to thus actuate the switch plunger.

2. In a switch actuating device for a switch having a plunger for its actuation, in combination, a base, a rotary element mounted on the base, a bearing stud eccentrically disposed on the rotary element, a bearing stud disposed on the base, a stressed flat spring disposed between the bearing studs, whereby rotation of said rotary element in a given direction decreases the distance between the bearing studs to thus bow the fiat spring to actuate the switch plunger.

3. In a switch actuating mechanism for a plunger actuated switch, the combination of, a housing, a shaft rotatably mounted in the housing, a plunger actuated type switch mounted in the housing, the axis of the switch actuating plunger and the shaft being in parallel relation, an actuator consisting of several elements operatively secured to the end of the shaft within the housing and adapted to produce a movement of an element of the actuator at right angles to the shaft, an elongated fiat spring under a bowed deflection disposed between the housing and the element to be bowed still more than the original deflection upon movement of the element to actuate the switch plunger upon rotary motion of the shaft.

4- A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a switch actuating plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in the housing wall, an actuating crank secured to its outer end, and an element operatively secured to the end of the shaft terminating in the housing for producing a crank-arm effect, a. fiat leaf spring, a. bearing on the housing for receiving one end of the spring, a bearing on the element for receiving the other end of the spring, whereby rotary operation of the shaft moves the end bearings of the spring toward each other to thus bow the spring, the spring bearings being so disposed with reference to the switch actuating plunger that rotary operation of the shaft bows the spring to operate the switch actuating plunger longitudinally of its axis.

5. A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a switch actuating plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in the housing wall, an actuating crank secured to its outer end, and an element operatively secured to the end of the shaft terminating in the housing for producing a crank-arm effect, a flat leaf spring, a bearing on the housing for receiving one end of the spring, a bearing on the element for receiving the other end of the spring, whereby rotary operation of the shaft moves the end bearings of the spring toward each other to thus how the spring, means operatively associated with the element for maintaining the initial bow of the spring in the direction of the switch actuating plunger, the spring bearings being so disposed with reference to the switch actuating plunger that rotary operation of the shaft bows the spring to operate the switch actuating plunger longitudinally of its axis.

6. A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in a wall of the housing having an end projecting into the housing and an end projecting outside of the housing, operating means secured to the end projecting outside of the housing for eifecting rotary motion of the shaft, an element secured to the end of the shaft projecting into the housing for producing a crank arm action of a limited extent for a given angular motion of the shaft, a flat leaf spring, a bearing on the housing for receiving the lower end of the spring, a bearing for the other end of the spring on the element, means for producing an initial bow in the spring in a direction of the plunger, said bearings for the spring being so disposed with reference to the plunger that angular rotation of the shaft efiects a bowing of the spring to actuate the plunger.

'7. A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in a wall of the housing having an end projecting into the housing and an end projecting outside of the housing, operating means secured to the end projecting outside of the housing for effecting rotary motion of the shaft, an eccentric secured to the end of the shaft within the housing, a slide actuated for rectilinear movement normal to the shaft axis upon rotation of the eccentric, a flat leaf spring, a fixed bearing for one end of the leaf spring, a bearing on the slide for the leaf spring, the disposition of the bearings for the spring ends is such that rectilinear movement of the slide bows the spring to actuate the plunger.

8. A. switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in a wall of the housing having an end projecting into the housing and an end projecting outside of the housing, operating means secured to the end projecting outside of the housing for effecting rotary motion of the shaft, an eccentric secured to the end of the shaft within the housing, a slide disposed in suitable guides in the housing normal to the shaft for rectilinear movement in a plane normal to the shaft axis, a coupling link between the eccentric and the slide for effecting rectilinear movement of the slide upon rotation of the shaft, a flat leaf spring, a bearing member on the slide for receiving one end of the spring, a fixed bearing for receiving the other end of the spring, the bearings being so disposed that rotary motion of the shaft bows the spring to actuate the plunger.

9. A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in a wall of the housing having an end projecting into the housing and an end projecting outside of the housing, operating means secured to the end projecting outside of the housing for effecting rotary motion of the shaft, an eccentric secured to the end of the shaft within the housing, a slide disposed in suitable guides in the housing normal to the shaft for rectilinear movement in a plane normal to the shaft axis, a coupling link between the eccentric and the slide for effecting rectilinear movement of the slide upon rotation of the shaft, a fiat leaf spring, a bearing member on the slide for receiving one end of the spring, a fixed bearing for receiving the other end of the spring, said spring being disposed under stress between the bearings so as to place an initial bow in the spring, means for making the initial bow be in a given. direction, the bearings being so disposed that rotary motion of the shaft bows the spring to actuate the plunger.

10. A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in a wall of the housing having an end projecting into the housing and an end projecting outside of the housing, operating means secured to the end projecting outside of the housing for effecting rotary motion of the shaft, a rotary element rotatably mounted on the end of the shaft within the housing, a stop for limiting the rotary motion, coupling means including a spring, and a crank arm secured to the inner end of the shaft for effecting a limited crank-arm movement of the rotary element upon rotation of the shaft in a given direction, a fiat leaf spring, a bearing member on the rotary element for receiving one end of the spring, a fixed bearing for receiving the other end of the spring, said fiat leaf spring being bowed between said bearings, the bearings being so disposed that rotary motion of the shaft bows the flat leaf spring still more to actuate the plunger.

11. A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a plunger mounted for operation longitudinally of its axis to actuate the switch, a shaft rotatably mounted in a wall of the housing having an end projecting into the housing and an end projecting outside of the housing, operating means secured to the end projecting outside of the housing for effecting rotary motion of the shaft, a rotary element rotatably mounted on the end of the shaft within the housing, a stop for limiting the rotary motion, coupling means including a spring, and a crank arm secured to the inner end of the shaft for effecting a limited crank-arm movement of the rotary element upon rotation of the shaft in a given direction, a fiat leaf spring, a bearing member on the rotary element for receiving one end of the spring, a fixed bearing for receiving the other end of the spring, said flat spring being disposed under stress between the bearings so as to place an initial bow in the flat spring, means for making the initial bow be in a given direction, the bearing-s being so disposed that rotary motion of the shaft bows the flat spring still more to actuate the plunger.

12. In a switch actuating device for a switch having a plunger for its actuation, in combination, a base, a rotary element mounted on the base, a fiat spring, a bearing disposed to be actuated by the rotary element, a bearing disposed on the base, said flat spring being disposed between 8 the bearings in a stressed condition, whereby rotation of said rotary element in a given direction decreases the distance between the bearings to thus bow the fiat spring to actuate the switch plunger.

13. A switch actuating mechanism including, in combination, a housing, a snap-action type switch mounted in the housing, a plunger mounted for operation longitudinally of its axis to actuate the switch, a straight flat spring, a bearing member mounted on said housing designed to receive one end of the flat spring, a shaft rotatably mounted in a wall of the housing having an end projecting outside of the housing, operating means secured to the end projecting outside of the housing for effecting rotary motion of the shaft, an actuator consisting of several elements operatively secured to the end of the shaft within the housing, a second bearing member designed to receive the other end of the flat spring, said second bearing member being operatively associated with the actuator, means for producing an initial bow in the spring in a direction of the plunger, said bearings for the spring being so disposed with reference to the plunger that the angular rotation of the shaft effects a further bowing of the spring to actuate the plunger.

RALPH B. IMMEL. LAWRENCE PIERCE. STANLEY KMONK, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,493,559 Norden May 13, 1924 1,676,155 Pfeifer July 3, 1928 1,680,428 Mottlau Aug. 14, 1928 1,973,800 Curtis Sept. 18, 1934 2,040,663 Mallet May 12, 1936 2,121,626 Degelman June 21, 1938 2,218,83 Wahl Oct. 22, 1940 

